Submersible salvage unit

ABSTRACT

A submersible salvage unit is provided with a central elongated pontoon to which are pivotally attached opposed pairs of downwardly depending arms for grasping a sunken vessel or other object. At points remote from their depending portions, the arms are connected to outer pontoons which can be actuated to move the arms from grasping to inoperative positions by relative vertical movement of these latter pontoons with respect to the central pontoon. The relative movements are effected by varying the buoyancy of the outer pontoons with respect to the central pontoon. Buoyancy compensators are provided in each of the pontoons to adjust their buoyancies to match the distribution of loads which are to be lifted, and for rapidly releasing buoyancy gas from the pontoons, if necessary, so that the buoyancy compensators on the pontoons also function as stabilizers to maintain the unit in a stable attitude when it is lifting a load. Self-contained gas generating means are provided to supply buoyancy gas to the interiors of the pontoons.

limited fitates Patent [191 llfiriedt et all.

[451 Jan.'1,1974

[ 1 SUBMERSHBLE SALVAGE UNHT [76] inventors: lFredericl-t A. llttriedt, 604 Alma St.

SE, Vienna, Va. 22180; Thomas H. Sundstrom, 5712 Chippewa Rd., Virginia Beach, Va. 23462; Richard Wallro, 15913 Martin Rd, Roseville, Mich. 48066 [22] Filed: Sept. 1, 1971 [21] Appl. No.: 177,074

[52] 1.1.8. (11. 114/52 [51] 1nt. Cl. 1863c 7/08 [58] Field 01 Search 114/51, 52, 44, 45; 9/8 R [56] References Cited UNITED STATES PATENTS 3,541,986 ll/1970 Kriedt et a1 114/52 1,854,026 4/1932 Gamba I 114/53 3,648,314 3/1972 Garrison 114/52 3,276,049 10/1966 Stixrud r 9/8 R 2,949,877 8/1960 Newborn et a1... 114/54 X 3,376,588 4/1968 Berteaux et a1... 9/8 R 3,471,877 10/1969 Bayles 9/8 R FOREIGN PATENTS OR APPLICATIONS 5,889 12/1883 Great Britain 114/45 1,062,509 4/1954 France 114/44 Primary Examiner-Milton Buchler Assistant Examiner-Gregory W. OConnor Attorney-Cushman, Darby & Cushman [5 7 ABSTRACT A submersible salvage unit is provided with a central elongated pontoon to which are pivotally attached opposed pairs of downwardly depending arms for grasping a sunken vessel or other object. At points remote from their depending portions, the arms are connected to outer pontoons which can be actuated to move the arms from grasping to inoperative positions by relative vertical movement of these latter pontoons with respect to the central pontoon. The relative movements are effected by varying the buoyancy of the outer pontoons with respect to the central pontoon. Buoyancy compensators are provided in each of the pontoons to adjust their buoyancies to match the distribution of loads which are to be lifted, and for rapidly releasing buoyancy gas from the pontoons, if necessary, so that the buoyancy compensators on the pontoons also function as stabilizers to maintain the unit in a stable attitude when it is lifting a load. Self-contained gas generating means are provided to supply buoyancy gas to the interiors of the pontoons.

20 Claims, 12 Drawing Figures SUBMERSTBLF. SALVAGE UNIT BACKGROUND AND BRIEF DESCRIPTION OF THE INVENTION This invention relates to the art of salvaging sunken vessels, or other objects, from a body of water, and in particular, the invention is concerned with improvements in salvaging units and methods of operation for retrieving sunken objects from deep water.

it is known in the prior art to provide for various structures and devices which function to assist in the salvage of sunken vessels such as, for example, by attachment of buoyancy tanks to a sunken vessel or by the use of a particularly designed salvage rig which can embrace and lift a sunken object. In the patents to Buell US. Pat. No. 1,616,410 and Powell U.S. Pat.,No. 1,691,738, there are described designs for rigs which are intended to be lowered into engagement with a sunken vessel for grasping and lifting of same. In the Buell'arrangement, grasping arms are actuated by a number of lines which must be manipulated from the surface, and Powell discloses a design for actuating grasping arms by adjusting the buoyancy of tanks which are rigidly connected to the grasping arms. A similar arrangement is also disclosed in the patents of Frances, US. Pat. No. 1,881,123 and Bontempi, US. Pat. No. 1,851,892

Although various designs and assemblies have been attempted in the past, it is in our experience that prior designs in assemblies have not solved the special problems of salvaging relatively large sunken vessels from deep water. it can be appreciated that the grasping and floating of the sunken vessels can be quite dangerous, and extremely unstable conditions can arise while the vessel is being lifted from its sunken position to the surface of a body of water. Actual salvaging operations in the past have involved substantial dangers to all personnel involved and much effort can be wasted if a vessel is lost from a salvaging rig during the floating or surfacing operation. In US. Pat. No. 3,541,986, granted Nov. 24, 1970 to same inventors as the present invention, a

salvaging unit was disclosed which avoided many of the foregoing problems. However, the range of depths in which the apparatus of our prior patent could be used safely was limited. The improvements of the present invention provide for greater safety and control of these operations in much greater depths than were obtainable by use of the prior art apparatus so that sunken vessels can be retrieved with relative safety and at costs which are acceptable to present day requirements even where the vessel has been lost in water that has previously been considered too deep for normal salvaging operations.

The salvaging unit of the present invention is of the type which can be floated to the location of a sunken vessel so as to be sunk over the vessel for grasping the same and lifting it to the surface of the body of water. The salvage unit includes an inner pontoon which has sufficient length and width to position two rows of grasping arms over and around a vessel which is to be lifted. On the under side of the inner pontoon, there are provided a plurality of depending plates on which are pivotally mounted two rows of grasping arms. Each grasping arm is formed with a depending portion on one side of a pivot mount and another portion which extends laterally outwardly from the inner pontoon. The outer ends of each of the grasping arms are each secured to outer pontoons disposed on opposite sides of the inner pontoon. By virtue of their pivotal connection, the grasping arms can be moved from an inoperative position where the two rows of arms are spread away from each other to an operative, grasping position, where the two rows of arms are moved toward each other and towards a central space beneath the inner pontoon. The actuation of the grasping arms is achieved simply by varying the buoyancy of the outer pontoons with respect to the inner pontoon, one outer pontoon being used to control the grasping arm on the opposite side of the unit whereby maximum leverage is obtained for the inward movement of the grasping arms toward the side walls of a vessel which is to be received and retained by the arms.

Each of the pontoons of the present invention is divided into a plurality of compartments of substantially the same volume and each is provided with a buoyancy compensator similar to that which is disclosed in our prior patent. The buoyancy compensators comprise tubular members which provide communication between the sealed interior of a compartment of a pontoon with the outside environment (the sea) so that controlled amounts of water can be admitted into pontoons to adjust their buoyancy. Means are provided for adjusting the distance at which the lowermost end of each buoyancy compensator extends into the interior space of a compartment of a pontoon. The tubular members comprising the compensators extend through an upper wall of each of the compartments of each of the pontoons so that when the grasping arms are in their open position, each of tubular members will extend in generally vertically parallel relation with each other tubular member. When the grasping arms are in their closed positions, however, the tubular members of the outer pontoons will be tilted towards each other so that their lower ends will be farther apart than when the grasping arms are in their open position. This arrangement, as will hereinafter more fully be described, will permit more rapid stabilization of the unit in the event that an unstable attitude occurs during the lifting operation and also avoids the necessity of providing additional means for rapidly venting buoyancy gas from the compartments.

In order to enable the salvage unit of the present invention to operate in substantially greater depths than have heretofore been possible, novel means are provided for supplying gas to the interior of the compartments of each pontoon, which means can be operated by remote control.

The salvage unit of the present invention permits the safe and controlled handling of sunken vessels or other objects without unreasonable or uneconomical requirements or additional devices. The foregoing and other features and advantages of the present invention will become apparent in the more detailed discussion which follows, and in that discussion, reference will be made to the accompanying drawings as described below.

BRIEF DESCRIPTTON OF THE DRAWTNGS FIG. 11 is an elevational schematic end view of the sal vage unit of this invention with the arm members in an open position;

FIG. 2 is a side elevational view of the salvage unit of FIG. 11 with the foam member removed;

FIG. 3 is an elevational schematic view of the salvage unit illustrating the arm members in a closed position;

FIG. 4 is a schematic illustration of the buoyancy compensating function of the buoyancy compensating means of one of the pontoon members of the present invention;

FIG. 5 is a schematic cross-sectional view of a compartment illustrating the operation and cooperation of the gas supplying means and the buoyancy compensators of the present invention;

FIG. 6 is a schematic end view of the salvage unit of the invention illustrating the relationship between the compensating units of the outer pontoon members in stabilizing the unit;

FIG. 7 is an enlarged view of an arm with part broken away;

FIG. 8 is an end view illustrating the salvage unit of the present invention in its towing position;

FIG. 9 is a schematic illustration of one embodiment of the gas supplying means of the present invention;

FIG. 10 is a schematic illustration of another embodiment of the gas supplying means of this invention;

FIG. II is still another embodiment of the gas supplying means; and

FIG. 12 is an illustration of means for adjusting the buoyancy compensators carried by the pontoon members.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, wherein like numerals designate corresponding parts throughout the several views, there is illustrated in FIG. I an end view of the salvage unit of the present invention generally designated at If), and in FIG. 2 a side view in elevation of the unit of FIG. I however with the foam member 88 removed. The salvage unit 10 comprises a complete rig which can be floated and towed to the location of a sunken vessel or object and then the unit can be aligned and sunk into a position over the vessel for receiving and retaining the vessel within opposed grasping arms associated with the unit. The salvage unit can be of any size and configuration, but it should be of sufficient dimensions to fully embrace and include whatever sunken vessel or other object is to be received within the grasp of its opposed arms. The particular constructional features and relationships which are offered by the present invention permit the use of such a very large salvage unit in operations which are controlled, safe and economical for salvaging requirements even in hitherto inaccessible depths. Also, there is provision for careful control and balancing of the buoyancy factors of the salvage unit so as to permit the unit to be safely used independent of any connection or linkages with a surface vessel or vessels during a salvaging operation.

The salvage unit includes a central pontoon member 12 and outer pontoon members 32 and 34 each in the form of elongated cylindrically shaped enclosures which function to provide strength and support to the entire unit and to components which are the working parts of the unit. It is important that a salvage unit, of the size contemplated by this invention, maintain its structural integrity while being floated and towed as well as during actual salvage operations. Accordingly, it will be understood by those skilled in the art that the materials and details of construction of the elements of the present invention must be appropriate to accommodate the vessels or other objects intended to be handled by the unit.

Each of the pontoons 12, 32 and 34 are provided on their top sides with a housing 14 which extends the length of the pontoons as shown in FIG. 2. On the underside of the pontoon member 12 there is provided a plurality of depending plate-like members 16. The depending members 16 are secured to the underside of pontoon 12in spaced apart groups with three members in each group. While only four of such groups are shown in FIG. 2, it will be understood that any desired number may be provided as will be required for the particular load to be lifted. A plurality of arm means one of which is designated at 18, are pivotally mounted on shafts 20 and 22 which, in turn, are secured in aligned bores formed in the plate members 16 on either side of the longitudinal axis of the pontoon member 12. As shown in FIG. 1, the plurality of arm means comprise several sets of opposed pairs of arms 24 and 26 which have portions as at 28 and 30 which extend laterally outwardly from the pivotal mounting connections 20 and 22. It should be understood that other mounting arrangements may be utilized for permitting movement of the arm means relative to the plate members 16. Each of the outer ends of the portions 28 and 30 of the arm means is securely attached to an exterior portion of outer pontoon members 32 and 34. As is seen in FIG. 1, pontoon member 32 is disposed on a side of pontoon member 12 opposite to the side on which pontoon member 34 is located and that pontoon member 32 will operate arms 24 while pontoon member 34 will operate arms 26. The arms means 18 function as grasping arms for engaging and retaining a sunken vessel within the confines of the space defined between the two rows of depending lower portions of such arms. The arrangement illustrated provides for maximum leverage and for better control of the rocking movements of individual arms about their pivotal connections on the member 16. In addition, this arrangement provides for a positive control of the arm movements by adjusting buoyancy conditions for the outer pontoon members 32 and 34 without requiring any adjustment in the buoyancy of the central pontoon member 12.

One of the difficulties in prior art designs for salvage units of the type which are intended to grasp and retain sunken vessels has been a lack of control in effecting movements of the grasping arms and this problem has been compounded by lack of control for maintaining a stable attitude of the sunken vessel once it is received into a salvage rig. The present invention provides improved means for controlling the attitude of the salvage unit and a vessel retained therein as the vessel is being lifted toward the surface of a body of water. In addition, the present invention provides means for supplying gas to each of the pontoon members so that the salvage unit can be operated independently of any mechanical connection or fluid pressure hose link with a surface vessel.

As illustrated in the drawings, each of the pontoon members is provided with buoyancy compensating means in the form of a plurality of hollow tubes 36. As shown schematically in FIG. 4, each pontoon member is divided into a plurality of sealed compartments 38, each of which is provided with its own buoyancy tube 36. With reference to FIG. 3, there is illustrated a valve system for each compartment 38 in each pontoon member. The valve system of each compartment of each pontoon is substantially identical so that the following description of the valve system of compartment 33 in pontoon 32 is to be understood as applying to the remaining compartments of pontoon members 112 and 3d. Adjacent the upper end d of tube 36, there is pro vided a butterfly-type valve 42 which is normally open during the salvaging operation. A second butterfly-type valve H is located in a passage through housing M which communicates with the interior of a compartment 38 and a third butterfly-type valve as is located in an opening of the bottom side of each compartment 3%. The set of valves designated as to in FIG. 3 serve as flood valves while the set of valves designated as 44 serve as vent valves. The set of valves in the tubes 36 are provided merely to seal the tubes when the salvaging unit is being towed to the site ofa sunlten vessel. For operation in relatively shallow waters hydraulic actuators are connected to each of the valve levers, one of which is indicated at 47, which are driven by hydraulic fluid supplied through flexible conduits connected to a hydraulic pump carried on board a surface vessel. in operations in greater depths, however a hydraulic pump may be carried in each. of the housings 114 which will be operated by remote control such as, for example, through the use of signal cables connected to a control console carried on board a conventional manned submersible diving unit. The flood and vent valves and dd on the outer pontoon members 32 and 3d, of course, are always actuated in unison while the flood and vent valves 46 and 44.- of the central pontoon member K2 are operated independently of the opera tion of the valves on the outer pontoon members in carrying out a salvaging operation, as will be more fully described hereinafter;

In FIG. 5, there is illustrated the disposition of conduits 418 and 50 which are carried in the housings 14 of each of the pontoon members and are connected at one end to a means for supplying gas to each of the compartments of each pontoon member. For operation in relatively shallow depths, the conduits 48 and 50 of each of the pontoon members can be supplied with pressurized fluid from a surface vessel by means of conventional hoses. in order to control the buoyancy of an individual compartment 38, the placement of each buoyancy compensator tube as is made adjustable. As. shown in H0. 5, each buoyancy compensator tube 36 comprises a straight tubular member which communicates between an outside environment (the sea) and the sealed interior space of an individual compartment 38. The lower most end 52 of a tube 36 is adjusted in its vertical level within the compartment 38 which is to be controlled, and during a normal salvaging operation the valves 42 of each compensator tube 36 will be open so that water can be passed into and out of a compartment 3% through its tube 36. When air, or other buoyancy gas, is introduced as through conduits 48 and 50 into a compartment, water will be displaced outwardly through the tube 36 once the pressure of the air or gas has equalized with the water pressure within the compartment. However, when the water level reaches the lowest end 52 of a tube 36, the air or gas will be allowed to escape through the exposed end 52 and no further water will be displaced from the compartment irrespective of the pressure of the compressed air or gas. Thus, the level at which the lowest most end 52 is extended into the compartment which is to be controlled determines the amount of water which will be left in the compartment when air or gas is introduced into the compartment. This provides for an automatic regulation of buoyancy conditions for each compartment by computing the amount of positive buoyancy which is required and by setting the buoyancy compensator to provide for that amount of positive buoyancy when air or gas is introduced. The buoyancy of a given compartment is adjusted by lifting or lowering a tube 36 as by the apparatus illustrated in FIG. 12 to a level which corresponds with the desired relationship of water volume and gas volume needed for a particular buoyancy force. The use of a hydraulic cylinder 54, piston 56 and piston rod 5% which is connected to the lower end 52 of a tube 36 is by way of example only and it will be understood that other conventional control means may be utilized. it should also be noted that the exterior surface of a tube as which extends through the upper wall of a compartment and through housings Mt must be provided with appropriate seals to prevent leakage of gas through the apertures provided for the tubes are. As will be pointed out hereinafter, the structure and arrangement of the compensating tubes as in the outer pontoon members 32 and 34 will provide very-sensitive control for the attitude of the salvaging unit as it is being raised to the surface so that there will be no necessity of adjusting the placement of individual tubes during the lifting stage of the salvaging operation.

in FIGS. 9, l0 and Ill, there are schematically illu trated three arrangements for generating and supplying gas to the interior of each of the compartments 38 of each of the pontoon members. in FIG. there is shown a gas generating system utilizing liquid hydrazine (N l h). The apparatus for generating the gas is generally indicated at 54 and is carried within the housings 14 of each of the pontoon members. The apparatus 54 includes a liquid hydrazine tank 56, an electric motor 58 and a reactor compartment so. The electric motor is battery driven and is used to pump the liquid hydrazinc from tank se to the reactor compartment so where the liquid hydrazine is passed over a hot catalyst such as resistance heated platinum coils the resulting products being principally hydrogen and nitrogen gases. The gases are passed through conduits 62 to conduits 48 and 50 to each of the compartments 3% which are divided by walls as in a pontoon member. The operation of the-electric motor can be remotely controlled from a submersible diving unit so that the foregoing arrangement will be particularly useful in operating in depths up to at least 20,000 feet. For operation in great depths, after the salvage units have been towed to the salvage site, liquid hydrazine may be pumped directly into each of the pontoons themselves instead of being stored in the separate tank ss. Suitable conduits (not shown) would be utilized to connect each of the chambers 38 of each of the pontoons to their respective pumps. It should be noted that while the hydrazine is being loaded into the respective chambers the salvage unit would be connected to a surface vessel to prevent it from sinking. Subsequent to the loading of the hydrazine into the pontoons, the salvage unit could be released to begin its descent to the sunken vessel. When it is desired to render the pontoon members buoyant, the pumps are actuated to feed the hydrazine from the interiors of the pontoons to the reactor compartments to generate the gases which are then fed back into the pontoon members until the liquid hydrazine level descends to the lower ends of the tubes 1%. With this arrangement, sufficient gas will be able to be produced to overcome the enormous pressures that exist at the 20,000 feet depths. When hydrazine is used as the gas generating material, it will be necessary that the compartments of the pontoon members be flushed with a non-ignitable gas such as CO as the salvage unit reaches the surface of the water. For this purpose CO containers may also be carried in the housings I4 of the pontoon members and connected to each of the compartments 38.

In FIG. 10 there is schematically illustrated an alternate gas generating and supplying means generally designated at 68 which utilizes liquid nitrogen or hydrogen which is stored in tank 70to be passed through a remote controlled valve 72 to evaporation coil 74 and from the coil 74 to the lines 48 and 50 leading to each of the compartments 38. As with the hydrazine arrangement of FIG. 9, the gas generating means 68 is also carried within the housings I4 ofeach of the pontoon members. Tank 70 of course should be provided with suitable insulation to minimize the boiling off of the liquid nitrogen or hydrogen contained therein. The arrangement of FIG. I is designed for operation in depths in the neighborhood of 10,000 feet but it should be understood that the arrangementsof both FIGS. 9 and 10 as well as the arrangement illustrated in FIG. 11 may be operated in lesser depths.

In FIG. 11, there is shown a system utilizing a receptacle 76 mounted in a housing 14 having tapered bottom walls which slope towards an outlet 80. One of such receptacles 76 is provided for each compartment 38 of each pontoon number. An appropriate quantity of hydride pellets are carried in each receptacle 76 and a mechanical dispenser 81 is provided to discharge the pellets into the compartments 38. The dispensers may be driven by small battery operated electric motors which are remote controlled. The hydride pellets will react with the sea water in compartment 38 and hydrogen gas will evolve. The dispenser 81 will continue to discharge pellets once activated since the compensator tubes 36 (not shown in FIGS. 9, 10, II) will continuously regulate the amount of sea water that can be displaced by the evolving gas.

A salvaging operation utilizing the apparatus of the present invention will now be described.

With reference to FIG. 8, the salvage unit 10 may be towed to the site where the salvage is to effected in an upside down condition by sealing all of the valves maneuvers 42, M and 46 of one of the outer pontoon members and the central pontoon I2 and by opening the flood and vent valves 46 and 44 of the oppositely disposed outer pontoon member. The weight distribution of the salvage unit is such that the center of gravity will be located as at 82 in FIG. 8 so that by flooding one of the outer pontoons the unit can be turned over to assume the attitude shown in FIG. 1 which is the salvaging position. Upon reaching the salvage site, the unit is turned over from its towing position (FIG. 8). It should be pointed out that the grasping arms are locked in their closed position during these maneuvers as by appropriately located slidable shafts or pins housed in compartments 29 (FIG. 2) which may be hydraulically actuated to secure the ends of the depending portion of one or more of the sets of arm means in their closed position by insertion through holes 17 formed in the arms and plate members 16 (FIG. 1).

To carry out a salvage operation in relatively shallow water, resort may be had to the buoy system set forth in our US. Pat. No. 3,541,986. The salvage unit of the present invention, however, is uniquely suited for carrying out operations in depths which render the aforementioned buoy system impractical or impossible. In one form, in order to increase the depth range of the salvage unit of the present invention, battery driven motors may be carried in housing 14 of the central pontoon 12 for driving positioning propellers 84 which are appropriately disposed on the exterior of housing 14 of pontoon 12, as shown in FIGS. I and 2. A manned submersible vessel is utilized to place transponders at previously calculated positions on the vessel or object to be salvaged. The salvage unit in turn is provided with a suitable array of hydrophones for picking up the signals from the transponders. Conventional means are. of course, provided for relaying the output of the hydro phones to a suitably programmed computer unit which may be carried on a surface vessel or on a conventional submersible so that the exact position of the salvage unit with respect to the sunken object can be calculated and the positioning propellers 84 actuated to guide the salvage unit to the sunken vessel.

Before the actual salvaging operation is initiated, the buoyancy compensating tubes 36 of each compartment of each pontoon member are adjusted by their respective piston and cylinder arrangements to match the buoyancy of the salvage unit with the calculated effective weight of the sunken vessel. As illustrated in FIG. 4, for example, it will be noted that the outermost tubes 36 are disposed to a lesser extent within their respective compartments 38 than the innermost tubes so that the innermost compartments will have a greater amount of water displaced therefrom than the outermost compartments where it is determined that the lifting force should be greater toward the center of a ship than at its bow or stern. To commence the sinking of the salvage unit, the outer pontoon members 32 and 34 are first flooded by first opening their vent valves 44 and flood valves 46 so that the unit will assume the position illustrated in FIG. I with the grasping arms in their open position. Next, the inner or central pontoon member 12 is flooded by opening its flood and vent valves causing the unit to commence sinking whereupon the respective vent and flood valves are closed while the valves 42 and each of the compensator tubes 36 remain open. By controlling the operation of the positioning propellers 84, the unit may be accurately aligned with the vessel or object to be raised as it sinks toward the vessel or object. In order to slow down the descent of the salvage unit as it approaches the sea floor, a plurality of chains 86 are attached to the underside of the outer pontoon members (see FIG. 1) to depend therefrom. The lengths of the chains should be much greater than the height of the unit 10 so that the chains will contact the sea floor before the lower portions of the grasping arms I8 come into contact with the vessel. As the chains gradually accumulate on the sea floor, the weight of the unit will be reduced correspondingly, thus slowing the descent rate of the unit. During towing of the salvage unit 10, the chains may be stored in compartments on the outer-pontoon members.

To assure that the salvage unit maintains an upright attitude as it descends toward the sea floor, a body of buoyant material such as alayer of epoxy resin material having a large quantity of hollow glass microspheres imbedded therein is carried on the top side of housing 14 of pontoon 12, as illustrated at 88 in FIG. I. The

body or layer 8% will provide an additional buoyant force to pontoon I2 as the unit descends. Hydraulic latching means 13 may be provided for retaining the layer W on the top side of housing M and conventional transponder units may be utilized to effect release of the layer W when the chains 86 contact the sea floor. The latch means 13 may consist of vertically extending arms having projections on their upper ends. The arms will fit into tubular channels formed in the foam body 88 with lands that are engaged by the projections. By rotating the arms about their vertical axes, the projections move off of the hands to release the body 8%}. As a matter of practice, the body 88 functions as a safety backup for maintaining the unit in a stable attitude during descent since the center pontoon 12 need not be flooded entirely to effect sinking the of the unit. In other words, by raising tubes 36 in this pontoon out of the pontoon, a gas bubble will be left which is compressed as the unit sinks. This bubble together with the foam body 88 will cooperate to maintain the unit in the desired attitude during descent. With the layer 88 removed, the buoyancy of the unit is decreased yet the weight of the unit is also decreasing as the chains 86 accumulate on the sea floor so that the descent of the unit will be gradual.

Once the unit is on the bottom and the unit aligned with the object to be lifted, operation of the grasping arms 13 may be initiated. Generally, the submersible salvage unit of this invention will operate in areas where the sea bottom is relatively soft; however, as shown in FIG. 7, a jetting system may be used for supplying water jets through conduit 9th to nozzles as which are provided on the lower portion of each of the arms of the unit to assist in the movement of the individual arms through mud or other soft bottom conditions. Also, the use of a water jet assists in eliminating the vacuum which is usually created by an initial lifting of a large vessel away from a soft bottom upon which it has been resting. Electric motors, hydrazine turbines or other devices may be carried in the arms as at 9d to operate pumping functions for the water jet system. Rubber pads as are attached to the inner sides of each of the arms of the unit to lessen the possibility of damage to the hull of the vessel being engaged thereby.

To effect engagement of a vessel, gas is supplied to the interior of each of the compartments 3% of each of the outer pontoon members 32 and 34 causing these pontoon members to become buoyant and move upwardly relative to the pontoon member 12, thus effecting the closing of the oppositely disposed grasping arms 2d and 215 about the hull of the vessel or object to be lifted. As previously noted, the buoyancy of each compartment of the outer pontoon members has been previously set by positioning the compensator tubes 3-6 therein so that once the gas supplying means are actuated they may be allowed to continuously operate until the salvage unit surfaces.

Once the sunken vessel or object is fully retained by the two rows of arms 2d and 26, as illustrated schematically in FIG. 6 at 98, the gas supplying means of the central pontoon member I2 is actuated to supply gas to the compartments of the central pontoon member so as to render the entire salvage unit, together with the vessel 98, positively buoyant so that the unit It) will commence its ascent to the surface of the water.

As shown in FIG. 6, with the two rows of arms 24 and as in their closed position,the tubes 36 of the outer pontoon members 32 and 3d are tilted toward each other with their upper ends closer together and their lower ends farther apart than when the arms are in their open position, which is illustrated in FIG. I. With this arrangement, should the salvage unit 10 begin to assume an unstable attitude such as that illustrated in FIG. 6 with respect to the horizontal axis Y-Y, the lower ends 52 of the tubes 36 in pontoon member 34 will be lifted out of the water to immediately com-- mence venting of gas therethrough while at the same time allowing sea water to flow through the tube as into the compartments of the pontoon member 34., thus increasing the weight of this pontoon member. In the compartments in pontoon member 32, on the other hand, the lower ends 52 of the compensator tubes 36 carried therein will be moved deeper into the water in the compartment, thus shifting the gas water interface. This will result in the gas which is being continuously supplied to the interior of each of the compartments on each of the pontoon members to displace the water outwardly through tube 36 until the gas water interface is again adjacent the lower end 52 of the tubes in porntoon member 32. As previously pointed out, this will result in a decrease in the weight of the associated pontoon member while the pontoon member on the opposite side of the central pontoon 12 will experience an increase in weight to counteract the forces tending to rotate the salvage unit Mi out of its stable position. Since the compensator tubes 36 in the outer pontoon members are tilted toward each other, such compensating operations will be effected much more quickly than if the tubes were disposed in parallel relation to each other. With reference to FlG. 4i, there is a representation of the manner in which each of the pontoon members automatically compensates for an unstable attitude existing along the longitudinal axes of the unit with respect to the axis of stability indicated by the line X-X. The compensating function is the same as that described with respect to FIG. 6 except that it will be noted that the tubes are not tilted with respect to one another but all lie in parallel planes. The sensitivity to unstable conditions, however, is essentially the same as that illustrated in FIG. ti since the tubes at the opposite ends of the pontoon members are spaced a much greater distance apart relative to the mid point of the pontoon members with a plurality of tubes being located intermediate the ends.

As the unit ascends from the sea floor, it may be desirable to slow the rate of ascent as the unit approaches the surface since the rate of ascent will generally increase as the water pressure decreases. To effect such slowing down of the unit's ascent, each of the compartments of the central pontoon member as well as each of the outer pontoons may be provided with a pressure gauge transducer which senses the pressure in each of the compartments and actuates the switch controlling the operation of the hydraulic pump connected to the piston and cylinders 54 and st of each of the compensator tubes 36 so that when a predetermined pressure is sensed, the compensator tubes may be moved upward with respect to the compartments water surface to vent gas therefrom and allow sea water to flow back into the compartments to increase their weight. During the initial stages of ascent, the chains do will retard the rate of ascent by gradually increasing the gross weight of the unit until the chains are fully extended again.

Once the salvage unit and vessel have surfaced, the gas supplying means are shut off and the valves 42 in the tubes 36 may be sealed and the unit with the vessel towed to a dry dock where the outer pontoon members may be flooded again to release the vessel. A floating dry dock can be used also particularly where it is impractical to tow the unit and vessel to a harbor.

The salvage unit which has been described is manufactured and assembled in accordance with known shipbuilding techniques. It may be manufactured from metal plate of suitable thickness, and various parts may be welded, or otherwise secured together, to produce a complete assembly.

Although the invention has been described with reference to a particular embodiment, it will be understood that variations in the described embodiment will become obvious to those skilled in this art. Also, certain modifications or additions can be made to the described structure. All obvious variations and modifications are intended to be included within the scope of this invention.

What is claimed is:

1. A submersible salvage unit which can be sunk in a body of water to engage and raise a sunken object to the surface, comprising in combination:

first pontoon means having a plurality of support members attached thereto for supporting arm means which can be actuated to contact and engage the sunken object, plurality of arm means each connected to one of said support members with a number of said arm means being connected to their respective support members and the remainder of said arm means being connected to their respective support members so that said number and said remainder of said arms means can be moved towards and away from each other to grasp and hold a sunken object while it is being raised to the surface, said number of said arm means being connected to second pontoon means and said remainder of said arm means being connected to third pontoon means, said second and third pontoon means being disposed on opposite sides of said first pontoon means and movable relative to said first pontoon means between first positions wherein said number and said remainder of said arm means are moved away from each other and second positions wherein said respective arm means are moved towards each other,

each of said pontoon means being provided with buoyancy compensating means including a hollow member having an upper end which can communicate with an environment surrounding said unit and a lower end which can communicate with the interior space within a pontoon means and means for adjusting the extent to which said lower end of the hollow member can be disposed in a pontoon means so as to define an interface between two separate fluids having two different densities, within a pontoon means, said hollow members being open ended tubes through which water can be passed into and out of said pontoon means, said tubes being straight and disposed in said respective pontoon means to lie in substantially parallel planes when said second and third pontoon means are in their said first positions and when said second and third pontoon means are in their said second positions, said tubes of said second and third pontoon means will be tilted towards each other with their upper ends closer together and their lower ends farther apart than when in said first positions.

2. The salvage unit as claimed in claim 1 wherein each of said pontoon means is provided with means for supplying gas to the interiors thereof for displacing liquid therefrom only to a level which is at said lower end of said hollow member.

3. The salvage unit as claimed in claim 1 wherein said first, second and third pontoon means are first. second and third elongated cylinders, respectively, each arranged with their respective longitudinal axes extending generally parallel to one another and said support members are attached in spaced apart relation to the exterior of said first cylinder on a side thereof opposite the side through which said upper end of said tube extends, and each of said arm means is pivotally con nected intermediate its ends to a said support member, said plurality of arm means having downwardly depending portions arranged in two rows defining a space between said depending portions into which a sunken object can be received, the ends of said number of said arm means remote from said depending portions being connected to said second cylinder and the ends of said remainder of said arm means remote from their respective depending portions being connected to said third cylinder.

4. The salvage unit as claimed in claim 1 wherein weight means are attached to said unit to depend a distance therefrom so that when said unit is sunk in a body of water said weight means will contact the bottom of the body of water before said unit engages the sunken object.

5. The salvage unit as claimed in claim 4 wherein said weight means are metal link chains which are attached to said second and third pontoon means.

6. The salvage unit as claimed in claim 2 wherein said gas supplying means includes means for generating a gas including a housing containing material from which a gas can be generated, a said housing being carried by each of said pontoon means, and means for effecting the generation of gas from said material.

7. The salvage unit as claimed in claim 6 wherein said material is liquid nitrogen and said means for effecting the generation of gas includes an evaporation coil communicating with said respective housings and the interiors of said respective pontoon means, said coil having valve means for controlling admission of said liquid nitrogen into said coil.

8. The salvage unit as claimed in claim 7 wherein remote control means are provided for actuating said valve means.

9. The salvage unit as claimed in claim 6 wherein said material is liquid hydrogen.

10. The salvage unit as claimed in claim 6 wherein said material is hydrazine.

11. The salvage unit as claimed in claim 6 wherein said material is a hydride and said means for effecting the generation of gas is a dispensing means for discharging said hydride material into a pontoon means.

12. Salvage unit as claimed as claim 3 wherein said first, second and third elongated cylinders are each divided into a plurality of individual compartments, the compartments of each cylinder being of substantially the same volume capacity, and extending from one end of each cylinder to the other end thereof, each of the compartments of each of said cylinders having one of said tubes extending downwardly therein, all the tubes of said cylinder extending parallel to each other and generally perpendicular to the longitudinal axis of a said cylinder.

13. The salvage unit as claimed in claim 12 wherein each of said cylinders is provided with means for supplying gas to the interiors of each of their respective compartments for displacing liquid therefrom only to a level which is at said lower end of said tubes.

14. The salvage unit as claimed in claim 17 wherein said gas supplying means includes means for generating a gas including a housing containing material from which a gas can be generated, a said housing being carried by each of said cylinders, and means for effecting the generation of gas from said material.

15. The salvage unit as claimed in claim 18 wherein said material is liquid nitrogen and said means for effecting the generation of gas includes an evaporation coil communicating with said respective compartments of a cylinder and said respective housing, said coil having valve means for controlling admission of said liquid nitrogen into said coil.

16. The salvage unit as claimed in claim 15 wherein remote control means are provided for actuating said valve means.

17. The salvage unit as claimed in claim 14 wherein said material is liquid hydrogen.

18. The salvage unit as claimed in claim 14 wherein said material is hydrazine.

19. The salvage unit as claimed in claim 14 wherein said material is hydride.

20. The salvage unit as claimed in claim 1 wherein said first pontoon means has the form of an elongated cylinder and an upper side, said upper side of said cylinder having a covering of buoyant material releasably secured thereto and means for releasing said buoyant material. 

1. A submersible salvage unit which can be sunk in a body of water to engage and raise a sunken object to the surface, comprising in combination: first pontoon means having a plurality of support members attached thereto for supporting arm means which can be actuated to contact and engage the sunken object, a plurality of arm means each connected to one of said support members with a number of said arm means being connected to their respective support members and the remainder of said arm means being connected to their respective support members so that said number and said remainder of said arms means can be moved towards and away from each other to grasp and hold a sunken object while it is being raised to the surface, said number of said arm means being connected to second pontoon means and said remainder of said arm means being connected to third pontoon means, said second and third pontoon means being disposed on opposite sides of said first pontoon means and movable relative to said first pontoon means between first positions wherein said number and said remainder of said arm means are moved away from each other and second positions wherein said respective arm means are moved towards each other, each of said pontoon means being provided with buoyancy compensating means including a hollow member having an upper end which can communicate with an environment surrounding said unit and a lower end which can communicate with the interior space within a pontoon means and means for adjusting the extent to which said lower end of the hollow member can be disposed in a pontoon means so as to define an interface between two separate fluids having two different densities, within a pontoon means, said hollow members being open ended tubes through which water can be passed into and out of said pontoon means, said tubes being straight and disposed in said respective pontoon means to lie in substantially parallel planes when said second and third pontoon means are in their said first positions and when said second and third pontoon means are in their said second positions, said tubes of said second and third pontoon means will be tilted towards each other with their upper ends closer together and their lower ends farther apart than when in said first positions.
 2. The salvage unit as claimed in claim 1 wherein each of said pontoon means is provided with means for supplying gas to the interiors thereof for displacing liquid therefrom only to a level which is at said lower end of said hollow member.
 3. The salvage unit as claimed in claim 1 wherein said first, second and third pontoon means are first, second and third elongated cylinders, respectively, each arranged with their respective longitudinal axes extending generally parallel to one another and said support members are attached in spaced apart relation to the exterior of said first cylinder on a side thereof opposite the side through which said upper end of said tube extends, and each of said arm means is pivotally connected intermediate its ends to a said support member, said plurality of arm means having downwardly depending portions arranged in two rows defining a space between said depending portions into which a sunken object can be received, the ends of said number of said arm means remote from said depending portions being connected to said second cylinder and the ends of said remainder of said arm means remote from their respective depending portions being connected to said third cylinder.
 4. The salvage unit as claimed in claim 1 wherein weight means are attached to said unit to depend a distance therefrom so that when said unit is sunk in a body of water said weight means will contact the bottom of the body of water before said unit engages the sunken object.
 5. The salvage unit as claimed in claim 4 wherein said weight means are metal link chains which are attached to said second and third pontoon means.
 6. The salvage unit as claimed in claim 2 wherein said gas supplying means includes means for generating a gas including a housing containing material from which a gas can be generated, a said housing being carried by each of said pontoon means, and means for effecting the generation of gas from said material.
 7. The salvage unit as claimed in claim 6 wherein said material is liquid nitrogen and said means for effecting the generation of gas includes an evaporation coil communicating with said respective housings and the interiors of said respective pontoon means, said coil having valve means for controlling admission of said liquid nitrogen into said coil.
 8. The salvage unit as claimed in claim 7 wherein remote control means are provided for actuating said valve means.
 9. The salvage unit as claimed in claim 6 wherein said material is liquid hydrogen.
 10. The salvage unit as claimed in claim 6 wherein said material is hydrazine.
 11. The salvage unit as claimed in claim 6 wherein said material is a hydride and said means for effecting the generation of gas is a dispensing means for discharging said hydride material into a pontoon means.
 12. Salvage unit as claimed as claim 3 wherein said first, second and third elongated cylinders are each divided into a plurality of individual compartments, the compartments of each cylinder being of substantially the same volume capacity, and extending from one end of each cylinder to the other end thereof, each of the compartments of each of said cylinders having one of said tubes extending downwardly therein, all the tubes of said cylinder extending parallel to each other and generally perpendicular to the longitudinal axis of a said cylinder.
 13. The salvage unit as claimed in claim 12 wherein each of said cylinders is provided with means for supplying gas to the interiors of each of their respective compartments for displacing liquid therefrom only to a level which is at said lower end of said tubes.
 14. The salvage unit as claimed in claim 13 wherein said gas supplying means includes means for generating a gas including a housing containing material from which a gas can be generated, a said housing being carrIed by each of said cylinders, and means for effecting the generation of gas from said material.
 15. The salvage unit as claimed in claim 14 wherein said material is liquid nitrogen and said means for effecting the generation of gas includes an evaporation coil communicating with said respective compartments of a cylinder and said respective housing, said coil having valve means for controlling admission of said liquid nitrogen into said coil.
 16. The salvage unit as claimed in claim 15 wherein remote control means are provided for actuating said valve means.
 17. The salvage unit as claimed in claim 14 wherein said material is liquid hydrogen.
 18. The salvage unit as claimed in claim 14 wherein said material is hydrazine.
 19. The salvage unit as claimed in claim 14 wherein said material is hydride.
 20. The salvage unit as claimed in claim 1 wherein said first pontoon means has the form of an elongated cylinder and an upper side, said upper side of said cylinder having a covering of buoyant material releasably secured thereto and means for releasing said buoyant material. 